Conventional detergents used in the vehicle care, warewashing and laundry industries include alkaline detergents. Alkaline detergents, particularly those intended for institutional and commercial use, in combination with the presence of hard water commonly result in heavy scale formation that is difficult to control, particularly in warewash applications at elevated temperatures. Alkaline detergents often contain polymers, phosphonates, phosphates, a chelating agents such as nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) to help control scale, remove soils, and/or sequester metal ions such as calcium, magnesium and iron.
Chelating agents and/or threshold agents are often used in high alkaline detergents because of their ability to solubilize metal slats and/or prevent calcium, magnesium and iron salts from precipitating. When calcium, magnesium and iron salts precipitate, the crystals may attach to the surface being cleaned and cause undesirable effects. For example, calcium carbonate precipitation on the surface of ware can negatively impact the aesthetic appearance of the ware, giving an unclean look.